Pant-type absorbent article

ABSTRACT

A pant-type absorbent article having an absorbent assembly having an absorbent core and a chassis, wherein the front and back portions are joined to each other along two opposite longitudinal side edges to define a waist-opening and a pair of leg-openings, at least one of the front and back portions has an elastic web material, a crotch portion located between the front portion and the back portion in the longitudinal direction of the article, the front portion having a length in the longitudinal direction, the back portion having a length in the longitudinal direction, and the crotch portion having a length in the longitudinal direction, the absorbent assembly overlapping a distance with both the front and back portions, the article having a longitudinal and a transverse direction, wherein the absorbent assembly overlaps no more than 20% of the surface area of each of the front and back portions.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 12/695,580, filed on Jan. 28, 2010 which is a divisional ofU.S. patent application Ser. No. 11/843,419, filed on Aug. 22, 2007,which is a continuation of International Application No.PCT/SE2005/000307, filed on Mar. 2, 2005, and which designates the U.S.The entire contents of the prior applications are incorporated herein byreference.

TECHNICAL FIELD

The present invention refers to a pant-type absorbent article such as apant diaper, a sanitary pant or incontinence garment, said articlecomprising an elastic web material.

BACKGROUND

Absorbent articles having defined core regions and chassis regions aresupposed to have a comfortable fit about the wearer. For pant articleslike pant diapers, sanitary pants and incontinence pants it is alsodesirable that the articles are capable of being pulled up and down overthe hips of the wearer to allow the wearer or caregiver to easily put onand remove the article when it has been soiled. It is known to make suchabsorbent pants with elasticized stretchable side portions and waistportion, usually comprising elastic members, such as elastic threads,contractably affixed between the backsheet and the topsheet.

It is further known to make portions of the chassis of absorbentarticles of an elastic material, such as stretch-bonded laminates. Suchlaminates may include a layer of meltblown elastomeric fibers which havebeen stretched and sandwiched between outer layers of spunbonded webs.

U.S. Pat. No. 6,552,245 discloses an extensible outer cover for anabsorbent article which provides a certain permanent deformation whensubjected to a tensile force. The extensible outer cover comprises anecked laminate in the form of one layer of a necked non-elastic filmand one layer of an elastic film. The films may be breathable.

WO 03/047488 discloses an elastic laminate comprising an elastic filmwhich on opposite sides is bonded to first and second non-elasticfibrous layers. The laminate is made by bonding the non-elastic fibrouslayers to the elastic film layer and subsequently stretching thecomposite material, causing the non-elastic materials to break. Theelastic film material may be of a breathable material. The laminate maybe incorporated in an absorbent article.

US 2004/0243086 discloses a disposable pant-like undergarment havingstretchable front and back portions, for example made of an elasticlaminate. An absorbent assembly is secured to the front and backportions.

Further examples of absorbent articles which in part are made of elasticlaminates are found in U.S. Pat. No. 6,476,289 and JP 10043235.

International applications PCT/SE2004/001004, PCT/SE2004/001005 andPCT/SE2004/001415 refer to absorbent articles comprising an outercoversheet in the form of an elastic laminate having improved propertiessuch as cloth-like feel and appearance.

To obtain good fit, improved comfort and security against leakage, it isimportant that absorbent articles have dimensions which match therelative dimensions of the wearer. The relative dimensions of thearticle are also important, so that the components or regions of thearticle are not excessively large or small relative to each other. Theoverall dimensions of the article and relative dimensions of itscomponents may also be adjusted so as to obtain an article with a morepant-like appearance. Elastic materials may be used to improve fit, butthese are often expensive, so a need exists for articles which areelastic in those parts where elasticity is important, yet may comprise(cheaper) inelastic material in those parts where elasticity is lessimportant. The correct choice of elastic and inelastic materials must bemade for the different components or regions of the article, thusbalancing the interests of economy and good fit of the article.

Furthermore, the elastic properties of the elastic web materials used inthe construction of the article must be preserved wherever possible.

There is still need for improvement of the properties of absorbentarticles comprising an elastic web material, such as an elasticlaminate, particularly their fit and appearance. The comfort and softfeel of absorbent articles of the above-mentioned type is alsoimportant. Furthermore, improvements in manufacturing methods allowmanufacturing costs to be kept to a minimum, which is important fordisposable articles, as they are discarded after a single use.

OBJECT AND SUMMARY

An object of the present disclosure is to provide a pant-type absorbentarticle which avoids the problems associated with known articles of thistype. This is achieved by a pant-type absorbent article (such as a pantdiaper, a sanitary pant or incontinence pant) said article having anabsorbent assembly comprising an absorbent core, and a chassis. Thechassis comprises a front portion and a back portion, which are joinedto each other along two opposite longitudinal side edges to define awaist-opening and a pair of leg-openings. At least one of the front andback portions comprises an elastic web material. The article furthercomprises a crotch portion located between the front portion and theback portion in the longitudinal direction of the article. The frontportion has a length (b1) in the longitudinal direction, the backportion has a length (b3) in the longitudinal direction, and the crotchportion has a length (b2) in the longitudinal direction. The absorbentassembly lies at least in said crotch portion and overlaps a certaindistance with both the front and back portions, and the article has alongitudinal (y) and a transverse direction (x).

According to one embodiment of the disclosure, the absorbent assemblyoverlaps no more than 20%, preferably no more than 10%, of the surfacearea of each of the front and back portions, as measured in an extendedstate of the article. The term “extended state” will be described morefully below.

In this way, the pant-type absorbent article provides good fit, improvedcomfort and security against leakage, as the article adapts to the shapeof the wearer's body more easily. Using a combination of portions inparticular parts of the article allows specification of the componentsmore easily, and selection of those which are most suitable in a givenportion.

In another embodiment of the disclosure, the article has a front halfdefined by the edges of the article and a transverse centre line of thearticle, and a rear half defined by the edges of the article and atransverse centre line of the article. The surface area of the fronthalf is between 80% and 90% of the surface area of the rear half, asmeasured in an extended state of the article.

In a further embodiment, the article has a maximum width (c) in thetransverse direction and a maximum length (b) in the longitudinaldirection. The ratio of the maximum width (c) to the maximum length (b)of the article is between 80% and 120%, preferably between 90% and 110%,as measured in an extended state of the article. Furthermore, the ratioof the length (b1) of the front portion to the width (c) of the articlemay be between 25% and 35%, preferably between 28 and 32%, as measuredin an extended state of the article. The ratio of the length (b3) of theback portion to the width (c) of the article may be between 38% and 52%,as measured in an extended state of the article.

The length (b2) of the crotch portion is between 10-40%, preferablybetween 20-40%, most preferably between 25-35% of the entire length ofthe article (b) as measured in an extended state of the article.

In one embodiment both of the front and back portions comprise saidelastic web material.

According to one aspect of the disclosure the crotch portion issubstantially free from said elastic web material and that the length ofthe crotch portion is substantially equal to the distance between panelsof the elastic web material in the front and back portion.

Preferably, the absorbent assembly comprises a liquid imperviousbacksheet layer, a liquid pervious topsheet layer and an absorbent coreenclosed therebetween.

In one embodiment, the crotch portion comprises crotch panel material,which is preferably a substantially inelastic web material, and whichunderlies the absorbent assembly on the garment-facing side thereof.Preferably, the inelastic web material is a nonwoven material.

According to one embodiment, the elastic web material is a laminatecomposed of first and second layers of fibrous material and an elasticfilm layer located between said first and second fibrous layers. In afurther embodiment, the elastic film layer is breathable.

In one aspect of the disclosure the elastic laminate has a Water VapourTransmission Rate according to ASTM E96-00 Procedure D of at least 1500g/m² 24 h, preferably at least 3000 g/m² 24 h.

According to one embodiment, said elastic laminate comprises first andsecond fibrous layers of spunbond material, each having a basis weightof between 10 and 35 g/m², preferably between 12 and 30 g/m², morepreferably between 10 and 25 g/m², and a breathable elastic film layerhaving a basis weight between 20 and 80 g/m², preferably between 20 and60 g/m², said elastic laminate having a Water Vapour Transmission Rateaccording to ASTM E96-00 Procedure D of at least 1500 g/m² 24 h,preferably at least 3000 g/m² 24 h.

According to a further embodiment, said elastic web material has anelasticity in the transverse direction of the article of at least 30%,preferably at least 50%, more preferably at least 70%, when measuredaccording to the elasticity test specified herein.

In one aspect of the disclosure the elastic web material has a basisweight of no more than 100 g/m², preferably no more than 90 g/m².

BRIEF DESCRIPTION OF DRAWINGS

Embodiments of the invention will be described in the following ingreater detail by way of example and with reference to the accompanyingdrawings, in which:

FIG. 1 shows a perspective view of a pant diaper according to anembodiment of the present invention.

FIG. 2 shows is a plan view of the pant diaper in its flat,fully-extended state prior to formation as seen from the body-facingside.

FIG. 3 is a corresponding plan view from the opposite, garment-facingside of the pant diaper.

FIG. 4 is a cross section according to the line VI-VI in FIG. 3.

FIG. 5 is a cross section through an elastic laminate according to theline VII-VII in FIG. 3.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Absorbent article

The term “absorbent article” refers to products that are placed againstthe skin of the wearer to absorb and contain body exudates, like urine,faeces and menstrual fluid. The invention mainly refers to disposableabsorbent articles, which means articles that are not intended to belaundered or otherwise restored or reused as an absorbent article afteruse. The invention refers to “pant-type absorbent articles”, having acore region and a chassis region surrounding the core region. Examplesof such pant-type absorbent articles are pant diapers, sanitary pantsand incontinence pants.

The drawings show an embodiment of a pant diaper 1 for an infant or anincontinent adult. Said pant diaper typically comprises an absorbentcore 2 located in the absorbent assembly 3 of the article. The diaperfurther comprises a chassis 4. The chassis comprises a front portion 5,a back portion 6. The article may comprise an elastic waist band 17.

The article has a longitudinal direction y and a transverse direction x.The absorbent assembly 3 comprises a liquid pervious topsheet 20 and aliquid impervious backsheet 19. The absorbent core 2 is enclosed betweenthe topsheet 20 and the backsheet 19 (FIG. 4).

Topsheet

The liquid pervious topsheet 20 can consist of a nonwoven material, e gspunbond, meltblown, carded, hydroentangled, wetlaid etc. Suitablenonwoven materials can be composed of natural fibers, such as woodpulpor cotton fibres, manmade fibres, such as polyester, polyethylene,polypropylene, viscose etc. or from a mixture of natural and manmadefibres. The topsheet material may further be composed of tow fibres,which may be bonded to each other in a bonding pattern, as e.g.disclosed in EP-A-1 035 818. Further examples of topsheet materials areporous foams, apertured plastic films etc. The materials suited astopsheet materials should be soft and non-irritating to the skin andintended to be readily penetrated by body fluid, e.g. urine or menstrualfluid. The topsheet may be different in different parts of the absorbentarticle.

Backsheet

The liquid impervious backsheet 19 comprised in the absorbent assembly 3on the garment-facing side of the absorbent core 2 is of a liquidimpervious material, such as a thin plastic film, e.g. a polyethylene orpolypropylene film, a nonwoven material coated with a liquid imperviousmaterial, a hydrophobic nonwoven material which resists liquidpenetration or a laminate comprising plastic films and nonwovenmaterials. The backsheet 19 may be breathable so as to allow vapour toescape from the absorbent core, while still preventing liquids frompassing therethrough. Examples of breathable backsheet materials areporous polymeric films, nonwoven laminates from spunbond and meltblownlayers, laminates from porous polymeric films and nonwovens. Thebacksheet 9 is preferably inelastic.

Elastic web material

At least one of the front and back portions 5 and 6 of the chassis 4comprises an elastic web material 10. Preferably both portions 5 and 6comprise elastic web material 10. The elasticity in the x-direction ofthe elastic web material 10 should be at least 30%, preferably at least50%, more preferably at least 70%, as measured by the elasticity testspecified herein.

Preferably the elastic web material 10 is also elastic in they-direction of the article. However the elasticity in the y-direction ispreferably lower than in the x-direction. The elasticity in they-direction should be at least 20%.

In the embodiment shown and described herein, the elastic web materialis an elastic laminate 10 composed of first and second outer layers offibrous material 11 and 12 and a middle elastic film layer 13 locatedbetween said fibrous layers (see FIG. 5). However it is understood thatother types of elastic web materials may be used, such as elasticnonwoven materials, nonwoven materials which are per se inelastic, butwhich have been elastified by means of elastic threads etc. The elasticweb materials may comprise one layer or two or more layers that havebeen laminated.

In the elastic laminate shown and described herein, it is preferred thatthe outer fibrous layers 11 and 12 are chosen so that they, incombination with the inner elastic film layer 13, give the material highresistance to puncture. They also provide a soft and cloth-like feel tothe laminate. Examples of suitable materials are carded webs andspunbond materials. The basis weight of the fibrous material layersshould be between 10 and 35 g/m², preferably between 12 and 30 g/m²,more preferably between 15 and 25 g/m². Examples of suitable polymersused in the fibrous materials are polyethylene, polyesters,polypropylene and other polyolefin homopolymers and copolymers. Naturalfibres, for example cotton, may also be used as long as they provide therequired properties. A mixture of polymers can contribute to a higherflexibility of the nonwoven layer, and through this, give the nonwovenmaterial a higher elongation at maximum load. A mixture of polyethyleneand polypropylene polymers has proved to provide good results in thisrespect. A mixture of fibers of different polymers is also possible.

The middle layer 13 is according to one embodiment of the invention anapertured elastic film having a basis weight between 20 and 80 g/m²,preferably between 20 and 60 g/m². The film may be of any suitableelastic polymer, natural or synthetic. Some examples of suitablematerials for the elastic film are low crystallinity polyethylenes,metallocene-catalyzed low crystallinity polyethylene, ethylene vinylacetate copolymers (EVA), polyurethane, polyisoprene, butadiene-styrenecopolymers, styrene block copolymers, such as styrene/isoprene/styrene(SIS), styrene/butadiene/styrene (SBS), orstyrene/ethylene-butadiene/styrene block copolymer. Blends of thesepolymers may also be used as well as other modifying elastomeric ornon-elastomeric materials. One example of a suitable film is anapertured three-layer elastomeric film of PE-SEBS-PE.

The total basis weight of the laminate is preferably 100 g/m² or less,more preferably no more than 90 g/m².

The elastic laminate 10 may be manufactured according to the methoddisclosed in WO 03/047488, wherein one spunbond layer 11 is applied tothe film 13 in a tacky state and will thus bond to the film layer, whilethe other spunbond layer 12 is adhesively laminated to the film layer13, using for example a pressure sensitive hot melt adhesive.Alternatively the laminate is manufactured according to a modifiedversion of this known method, wherein the modification involves that thelaminate is incrementally stretched (through intermeshing gears, IMG),to a point below the elongation at peak load of at least one of thenon-elastic nonwoven layers to retain some strength for at least one ofthe nonwoven layers. The other layer may also be stretched to a pointbelow its elongation at peak load, or to a point at which it will tearduring stretching.

The method disclosed in WO 03/047488 involves stretching of the laminateabove the point of failure of the fibrous material, so that thenon-elastic layers break completely. Therefore, as described in WO03/047488, the elongation of the laminate is not limited by the stretchmodulus of the non-elastic material.

In a preferred embodiment at least one, preferably both fibrous layers,which are bound to the elastic film, are (in contrast to the methoddescribed in WO 03/047488) not completely torn upon manufacture of alaminate according to the present invention. Selection of fibrousmaterials which have an elongation at maximum load greater than theelasticity of the elastic laminate allows the elastic film to stretchwithout being hindered by the fibrous layers. Such a selection alsoensures that the fibrous layers contribute to the puncture resistance ofthe laminate, as they are not completely torn or broken duringmanufacture. Preferably both fibrous layers or at least one of thefibrous layers have an elongation at maximum load that is at least 10%higher than the elasticity of the laminate. This is described in moredetail in PCT/SE2004/001005, which is incorporated herein by reference.

The opacity of a material layer is the characteristic ability of thematerial layer to visually hide from view an underlying object orpattern. The opacity is measured in %, wherein 100% opacity means thatnothing can be seen through the material layer and 0% means that thematerial layer is completely transparent. The opacity is measured by theOpacity Test described below, which is based onluminous-reflectance-factor data.

Opacity of the laminate can be obtained by the incorporation ofopacifying fillers into the laminate, particularly into the elasticfilm. Such pigments can be organic or inorganic dyes, colouring agents,or whitening agents. Inorganic materials such as titanium dioxide,inorganic carbonates, synthetic carbonates, talc, nepheline syenite,magnesium hydroxide, aluminium trihydrate siatomaceous earth, mica,natural or synthetic silicas, calcinated clays and mixtures thereof areall examples of preferred opacifying fillers.

The filler is preferably added as a master batch at the extrusion of thefilm. One example of an appropriate concentration is about 5% filler byweight of the film.

It is further preferred that the elastic laminate 10 has a breathability(Water Vapour Transmission Rate) according to ASTM E96-00 Procedure D ofat least 1500 g/m² 24 h, preferably at least 3000 g/m² 24 h.

The open area of the elastic film layer is preferably at least 5%, morepreferably at least 8%. The open area is measured by image analysismethods and is defined as the sum of the hole area divided by the totalarea of the film sample.

Absorbent core

The “absorbent core” is the absorbent structure disposed in theabsorbent assembly of the absorbent article. The absorbent core 2 can beof any conventional kind. Examples of commonly occurring absorbentmaterials are cellulosic fluff pulp, tissue layers, highly absorbentpolymers (so called superabsorbents), absorbent foam materials,absorbent nonwoven materials or the like. It is common to combinecellulosic fluff pulp with superabsorbent polymers in an absorbent core.Superabsorbent polymers are water-swellable, water-insoluble organic orinorganic materials capable of absorbing at least about 20 times itsweight and in an aqueous solution containing 0.9 weight percent ofsodium chloride. Organic materials suitable for use as a superabsorbentmaterial can include natural materials such as polysaccharides,polypeptides and the like, as well as synthetic materials such assynthetic hydrogel polymers. Such hydrogel polymers include, forexample, alkali metal salts of polyacrylic acids, polyacrylamides,polyvinyl alcohol, polyacrylates, polyacrylamides, polyvinyl pyridines,and the like. Other suitable polymers include hydrolyzed acrylonitrilegrafted starch, acrylic acid grafted starch, and isobutylene maleicanhydride copolymers and mixtures thereof. The hydrogel polymers arepreferably lightly crosslinked to render the material substantiallywater insoluble. Preferred superabsorbent materials are further surfacecrosslinked so that the outer surface or shell of the superabsorbentparticle, fiber, flake, sphere, etc. possesses a higher crosslinkdensity than the inner portion of the superabsorbent. The superabsorbentmaterials may be in any form suitable for use in absorbent compositesincluding particles, fibers, flakes, spheres, and the like.

A high absorption capacity is provided by the use of high amounts ofsuperabsorbent material. For an absorbent core comprising a matrix ofhydrophilic fibers, such as cellulosic fibers, and superabsorbentmaterial, the proportion of superabsorbent material is preferablybetween 10 and 90% by weight, more preferably between 30 and 70% byweight.

It is conventional in absorbent articles to have absorbent corescomprising layers of different properties with respect to liquidreceiving capacity, liquid distribution capacity and storage capacity.The thin absorbent bodies, which are common in for example baby diapersand incontinence guards, often comprise a compressed mixed or layeredstructure of cellulosic fluff pulp and superabsorbent polymers. The sizeand absorbent capacity of the absorbent core may be varied to be suitedfor different uses such as for infants or for adult incontinent persons.

The absorbent core may further include an acquisition distribution layerplaced on top of the primary absorbent body and which is adapted toquickly receive and temporarily store discharged liquid before it isabsorbed by the primary absorbent core. Such acquisition distributionlayers are well known in the art and may be composed of porous fibrouswaddings or foam materials.

Pant diaper

The pant diaper disclosed in FIG. 1 is intended to enclose the lowerpart of the wearer's trunk like a pair of underwear. It comprises anabsorbent assembly 3 and a chassis 4. The chassis 4 comprises a frontportion 5 and a back portion 6. The front 5 and back portions 6 arejoined to each other along two opposite longitudinal side edges byultrasonic welds, glue strings or the like to define a waist-opening anda pair of leg-openings of the pant diaper.

At least one and preferably both of the front and back portions 5,6comprises an elastic web material 10 as described above. The absorbentassembly 3 lies at least in said crotch portion 7 and overlaps a certaindistance with both the front and back portions 5; 6, and the article hasa longitudinal (y) and a transverse direction (x).

The article 4 further comprises a crotch portion 7 located between thefront portion 5 and the back portion 6 in the longitudinal direction ofthe article. The front portion 5 has a length b1 in the longitudinaldirection, the back portion 6 has a length b3 in the longitudinaldirection, and the crotch portion 7 has a length b2 in the longitudinaldirection.

The article is thus divided into three portions (front portion, crotchportion and back portion) in its longitudinal direction, as shown inFIG. 2. The front portion is defined by the waist edge of the article,the longitudinal side edges of the article, part of the leg openings ofthe article and a transverse line which is located at the point at whichthe angle of the edge of the leg opening changes most abruptly (i.e. thepoint at which the rate of change of the angle of the edge of the legopening with respect to the transverse direction is highest). The backportion is defined in a similar manner: by the waist edge of thearticle, the longitudinal side edges of the article, part of the legopenings of the article and a transverse line which is located at thepoint on the edge of the leg opening at which the angle of the edgechanges most abruptly (i.e. the point at which the rate of change of theangle of the edge of the leg opening with respect to the transversedirection is highest). The crotch portion is defined on the longitudinaledges by the edges of the leg openings of the article and on thetransverse edges by the two transverse lines described above.

It is important that the elastic web material of the front/rear portionsis allowed to flex and stretch when the article is in use. Ifnon-elastic layers are joined to this elastic web material, itsflexibility and extensibility is reduced. According to embodiments ofthe invention, the absorbent assembly 3 overlaps no more than 20%,preferably no more than 10%, of the surface area of each of the frontand back portions, as measured in an extended state of the article.

The “extended state” of the article is herein defined as a state inwhich the article has been extended in all four directions to such anextent that all the elastic materials contained therein, such as theelastic web material, the waist elastics, the leg elastics, are extendedto such an extent that they will not gather any part of the product, butthe entire products is completely flat. The article is extended only tosuch an extent that this flat condition is reached.

In another embodiment of the invention, the article has a front half 14defined by the edges of the article and a transverse centre line 16 ofthe article, and a rear half 15 defined by the edges of the article anda transverse centre line 16 of the article. The surface area of thefront half 14 is between 80% and 90% of the surface area of the rearhalf 15, as measured in an extended state of the article. This providesa more pant-like shape of the absorbent article.

In a further embodiment, the article has a maximum width (c) in thetransverse direction and a maximum length (b) in the longitudinaldirection, and the ratio of the maximum width (c) to the maximum length(b) of the article is between 80% and 120%, preferably between 90% and110% as measured in an extended state of the article. According to apreferred embodiment, the ratio of the length (b1) of the front portionto the width (c) of the article (b1/c) is between 25% and 35%,preferably between 28% and 32%, as measured in an extended state of thearticle. Additionally, the ratio of the length (b3) of the back portionto the width (c) of the article (b3/c) is between 38% and 52%, asmeasured in an extended state of the article. Articles conforming tothese measurements provide a more pant-like shape of the absorbentarticle and a more secure fit.

To provide good fit and security against leakage, the length (b2) of thecrotch portion 7 should be between 10-40%, preferably between 20-40%,most preferably between 25-35% of the entire length of the article (b)as measured in an extended state of the article.

The crotch portion 7 may comprise crotch panel material 21 whichunderlies the absorbent assembly on the garment-facing side thereof.

According to one embodiment of the invention, the crotch panel material21 comprises substantially inelastic web material 18, although elasticmaterials may also be used. Suitably, the inelastic web material 18 is anonwoven material. The substantially inelastic web material 18 isarranged in the crotch portion of the article and may be joined to theelastic web material 10 at or close to the borderline between the crotchportion 7 and the front and back portions 5 and 6 respectively such thatit is located between these portions in a longitudinal direction of thearticle. Although it may overlap with the front and back portions 5, 6sufficiently to be joined to these portions, the inelastic web material18 does not significantly overlap with front or back portions 5,6 overthe majority of its surface.

In one embodiment of the invention both of the front and back portionscomprise the elastic web material 10, while the crotch portion 7 issubstantially free from the elastic web material, wherein the length(b2) of the crotch portion 7 is substantially equal to the distancebetween panels of the elastic web material 10 in the front and backportions 5 and 6. However the borderline between the front and backportions 5 and 6 and the crotch portion 7 may or may not coincide withthe joints between the different panel materials 10 and 21. Thus jointsbetween different panel materials may extend over any of the front, backor crotch portions.

The inelastic web material 18 of the crotch portion 7 may be joined tothe elastic web material 10 of the front and/or back portions 5,6 whilethis is held in a selectively stretched condition, so that gathers arepresent in the inelastic web material 18 in the front and back crotchportion seams 8,9. The gathers act to draw the pant-type absorbentarticle to the required shape, thus providing a good fit, and alsoproviding the article with an appearance which is more pant-like.

In another embodiment, no separate crotch panel material 21 is provided,but the elastic web material 10 also underlies the absorbent assembly 3in the crotch portion of the article. Alternatively, the absorbentassembly 3 alone bridges the front and back portions 5 and 6.

The absorbent assembly 3 according to an embodiment of the inventioncomprises a liquid impervious backsheet layer 19, a liquid pervioustopsheet layer 20 and an absorbent core 2 enclosed therebetween, all ofwhich components are described above. The absorbent assembly 3 may bejoined to the elastic web material 10 of the front and/or back portions5, 6 while this is held in a selectively stretched condition, so thatgathers are present in the absorbent assembly 3 at those points where itis joined to the front and back portions 5, 6.

The pant-type absorbent article according to an embodiment of theinvention may comprise an elastic waist band 17 comprising elasticmembers secured to the front and back portion. In an alternativeembodiment only one of the front 5 and back portions 6 have an elasticwaist band 17 secured thereto. The elastic waist band portions 17 whichare secured to the front portion 5 and the back portion 6, respectively,may also be joined to each other along said side seams.

No additional elasticized side portions joining the front and backportions 5 and 6 are needed when using the elastic web material 10. Ifdesired, additional elasticized side portions may of course be provided,especially in cases where the elastic web material 10 is arranged onlyin parts of the front and/or back portions.

As stated above the elastic web material 10 has an opacity of at least40%, preferably at least 50% and more preferably at least 60%. Theopacity of the elastic web material provides a cloth-like appearance tothe article, which is of particular importance when the article is apant diaper. Especially in this case, where the elastic web materialforms the sole component in considerable surface area regions of thepant diaper, such as large areas of the front and back portions, and theabsorbent core covers only relatively small areas, 30% or less, of thearticle, the appearance of the elastic web material is of greatimportance for the overall appearance of the article. Thus by making theelastic web material opaque with an opacity of at least 40%, the pantdiaper will appear more cloth-like and more like “normal” underwear,than if the elastic web material would have a higher degree oftransparency. The opacity is measured by the Opacity Test disclosed inPCT/SE2004/001415.

It is further desired that the elastic web material has a punctureresistance of at least 15N as measured according to ASTM DesignationD3763-02. Preferably, the elastic web material of the present inventionhas a puncture resistance of at least 20N, and more preferably at least30N.

The elastic web material should preferably have a softness according toKawabata of at least 20, preferably at least 30 and most preferably atleast 40. It is further desired that it has a formability according toKawabata of no more than 50, preferably no more than 30, more preferablyno more than 20 and most preferably no more than 10. It is also desiredthat the elastic web material has a drapability according to Kawabata ofno more than 40. The softness, formability and drapability according tokawabata are measured according to the test methods given inPCT/SE2004/001004.

Elasticity test

The method measures how an elastic material behaves at repeated load andunload cycles. The sample is stretched to a predetermined elongation anda cyclic movement between 0 and said predetermined elongation isperformed. Desired load and unload forces are recorded. The permanent,i.e. remaining, elongation of the relaxed material is measured.

A tensile tester, Lloyd LRX, able to perform cyclic movements andequipped with a printer/plotter or software presentation is used. Thesample is prepared by cutting it to a width of 25 mm and a length thatis preferably 20 mm longer than the distance between the clamps in thetensile tester.

The tensile tester is calibrated according to the apparatusinstructions. The parameters needed for the test (load and unloadforces) are adjusted to:

Crosshead speed: 500 mm/min Clamp distance: 50 mm Preload: 0.05 N

The sample is placed in the clamps according to the marks and it is madesure that the sample is centred and fastened perpendicularly in theclamps. The tensile tester is started and three cycles between 0 and thepredetermined elongation, equal to the highest defined 1st load, areperformed. Before the last cycle, the sample is relaxed for 1 minute,and the permanent elongation is measured by stretching the sample untila force of 0.1 N is detected and the elongation is read.

The permanent elongation after relaxation should be less than 10% and ismeasured by the method above. Thus an elasticity of 30% is defined asthat the laminate should have a permanent relaxation after elongation ofless than 10% after being exerted to an elongation of 30% in the tensiletester above. An elongation of 30% means an elongation to a length thatis 30% longer than the initial length of the sample.

Dimensions

Some embodiments of the inventive articles have the following dimensionsand relative dimensions:

Crotch portion Product Back Front Crotch length width (c)/ portionportion portion (b2)/ product length (b3)/ length (b1)/ length productlength product product (b2)/product length Product (b); % width (c); %width (c); % width (c); % (b); % 1 92 47 29 24 26 2 92 50 32 18 20 3 10839 30 31 29Overlap of absorbent assembly on front/back portions

Product % Overlap, back % Overlap, back 1 15 5 2 12 12

It is understood that although the invention has been described withreference to preferred embodiments, several modifications are possiblewithin the scope of the claims and equivalents thereof. The inventiontherefore intends to cover any variations or equivalents which arewithin known or customary practice within the technical field to whichit belongs.

What is claimed is:
 1. A pant-type absorbent article comprising alongitudinal direction, a transverse direction, a longitudinalcenterline, and an absorbent assembly comprising an absorbent core and achassis, said chassis comprising a front portion and a back portion,wherein the front and back portions are joined to each other along twoopposite longitudinal side edges to define a waist-opening and a pair ofleg-openings, at least one of the front and back portions comprises anelastic web material, the elastic web material extending continuouslyfrom one longitudinal side edge of the front portion or the backportion, across the longitudinal centerline, and to the otherlongitudinal side edge, said article further comprising a crotch portionlocated between the front portion and the back portion in thelongitudinal direction of the article, said front portion having alength (b1) in the longitudinal direction, said back portion having alength (b3) in the longitudinal direction, and said crotch portionhaving a length (b2) in the longitudinal direction, said absorbentassembly lying at least in said crotch portion and overlapping a certaindistance with both the front and back portions, said article having awaist elastic member on each of the front portion and the back portionand extending from one longitudinal side edge of the front portion andthe back portion, respectively, across the longitudinal centerline, andto the other longitudinal side edge of the front portion and the backportion, respectively, and said article having a maximum width (c) inthe transverse direction and a maximum length (b) in the longitudinaldirection, wherein a ratio of the maximum width (c) to the maximumlength (b) of the article is between 90% and 110% as measured in anextended state of the article.
 2. The pant-type absorbent articleaccording to claim 1, wherein the length (b2) of the crotch portion isbetween 10-40% of the entire length of the article (b) as measured in anextended state of the article.
 3. The pant-type absorbent articleaccording to claim 1, wherein, both of the front and back portionscomprise said elastic web material.
 4. The pant-type absorbent articleaccording to claim 3, wherein the crotch portion is substantially freefrom said elastic web material and the length (b2) of the crotch portionis substantially equal to the distance between panels of the elastic webmaterial in the front and back portion.
 5. The pant-type absorbentarticle according to claim 1, wherein the absorbent assembly comprises aliquid impervious backsheet layer, a liquid pervious topsheet layer andthe absorbent core enclosed therebetween.
 6. The pant-type absorbentarticle according to claim 1, wherein the crotch portion comprises acrotch panel material underlying the absorbent assembly on the garmentfacing side thereof.
 7. The pant-type absorbent article according toclaim 6, wherein the crotch panel material comprises substantiallyinelastic web material.
 8. The pant-type absorbent article according toclaim 7, wherein the inelastic web material is a nonwoven material. 9.The pant-type absorbent article according to claim 1, wherein theelastic web material is a laminate composed of first and second layersof fibrous material and an elastic film layer located between said firstand second fibrous layers.
 10. The pant-type absorbent article accordingto claim 9, wherein said elastic layer is a film layer that isbreathable.
 11. The pant-type absorbent article according to claim 10,wherein said elastic laminate has a Water Vapour Transmission Rateaccording to ASTM E96-00 Procedure D of at least 1500 g/m2 24 h.
 12. Thepant-type absorbent article as claimed in claim 9, wherein said laminateelastic web material comprises first and second fibrous layers ofspunbond material, each having a basis weight of between 10 and 35 g/m2and the elastic layer is a breathable elastic film layer having a basisweight between 20 and 80 g/m2, said elastic laminate having a WaterVapour Transmission Rate according to ASTM E96-00 Procedure D of atleast 1500 g/m2 24 h.
 13. The pant-type absorbent article according toclaim 1, wherein the elastic web material has a basis weight of no morethan 100 g/m2.
 14. The pant-type absorbent article according to claim 1,wherein said elastic web material has an elasticity in the transversedirection of the article of at least 30%, when measured according to theelasticity test specified in the description.
 15. The pant-typeabsorbent article according to claim 1, wherein the elastic web materialhas an elasticity in the longitudinal direction of the article of atleast 20% when measured according to the elasticity test specified inthe description.
 16. The pant-type absorbent article according to claim1, wherein the absorbent assembly overlaps more than 0% and no more than20% of the surface area of each of the front and back portions, so thatthe absorbent assembly overlaps more than 0% and no more than 20% of thesurface area of the elastic layer, as measured in an extended state ofthe article.
 17. The pant-type absorbent article according to claim 1,wherein the length (b2) of the crotch portion is between 25-35% of theentire length of the article (b) as measured in an extended state of thearticle.
 18. The pant-type absorbent article according to claim 1,wherein the pant-type absorbent article comprises a longitudinalcenterline, and the elastic web material extends continuously from onelongitudinal side edge of the front portion or the back portion, acrossthe longitudinal centerline, and to the other longitudinal side edge.19. The pant-type absorbent article according to claim 1, wherein theentirety of at least one of the front and back portions comprises anelastic web material.
 20. The pant-type absorbent article according toclaim 1, wherein substantially all of at least one of the front and backportions is formed of an elastic web material that comprises an elasticlayer located between first and second fibrous layers such that theelastic web material exhibits at least 30% elasticity in the transversedirection, and the article further comprises a leg elastic.